Work is proposed to develop, in a systematic manner, the materials and techniques necessary to make tooth-like pit and fissure sealants a reality. Our previous work has shown that sintered apatite material shows great promise for this application, and that laser energy can be used to yield a carefully controlled thermal environment. It is considered that the combination of these two items, along with careful study and much work, can yield a highly durable sealant. Aspects of the proposed work include: 1) items related to the understanding of laser interaction with key materials, 2) basic materials development, and 3) application and evaluation of sealants. In the first category, items for consideration include evaluation of optical properties of tooth enamel and the sealant materials. This in turn is to be used to select the most appropriate laser for the desired application. Selection or development of appropriate laser energy delivery systems appropriate for clinical application is also necessary. In materials development, emphasis will be on two aspects-- optimization of materials which are sintered by techniques we have previously developed, and developing materials by new techniques appropriate to laser sintering on the tooth. This latter category includes alteration of stoichiometry, introduction of a low melting point second phase and use of reactive ingredients. Work in the third category will include development of practical techniques of fuzing sealants to the tooth. Several methods of application will be tried and evaluated by quantitative techniques. After successful techniques have been developed in vitro, tests will be performed in vivo in animals.